Expanding vaso-occlusive device

ABSTRACT

This is a device for occluding a space within the body. In particular, the device comprises an expandable member, an inner member and one or more stop elements. The devices may be placed in a desired site within a mammal to facilitate the formation of an occlusion.

FIELD OF THE INVENTION

Compositions and methods for repair of aneurysms are described. Inparticular, vaso-occlusive devices are disclosed, as are methods ofmaking and using these devices.

BACKGROUND

An aneurysm is a dilation of a blood vessel that poses a risk to healthfrom the potential for rupture, clotting, or dissecting. Rupture of ananeurysm in the brain causes stroke, and rupture of an aneurysm in theabdomen causes shock. Cerebral aneurysms are usually detected inpatients as the result of a seizure or hemorrhage and can result insignificant morbidity or mortality.

There are a variety of materials and devices which have been used fortreatment of aneurysms, including platinum and stainless steelmicrocoils, polyvinyl alcohol sponges (Ivalone), and other mechanicaldevices. For example, vaso-occlusion devices are surgical implements orimplants that are placed within the vasculature of the human body,typically via a catheter, either to block the flow of blood through avessel making up that portion of the vasculature through the formationof an embolus or to form such an embolus within an aneurysm stemmingfrom the vessel. One widely used vaso-occlusive device is a helical wirecoil having windings which may be dimensioned to engage the walls of thevessels. (See, e.g., U.S. Pat. No. 4,994,069 to Ritchart et al.) Otherless stiff helically coiled devices have been described, as well asthose involving woven braids. See, e.g., U.S. Pat. No. 6,299,627.

U.S. Pat. No. 5,354,295 and its parent, U.S. Pat. No. 5,122,136, both toGuglielmi et al., describe an electrolytically detachable embolicdevice. Vaso-occlusive coils having little or no inherent secondaryshape have also been described. For instance, co-owned U.S. Pat. Nos.5,690,666; 5,826,587; and 6,458,119 by Berenstein et al., describescoils having little or no shape after introduction into the vascularspace. U.S. Pat. No. 5,382,259 describes non-expanding braids covering aprimary coil structure.

U.S. patent application Ser. No. 10/745,911, filed Dec. 23, 2003 andincorporated herein by reference in its entirety, discloses emboliccompositions comprising an expandable element that is free fromhydrogels that expands along its primary axis upon deployment.

However, none of the above documents show a device as described hereinincluding one or more stop elements that allow for ease of movement ofthe device during placement, re-positioning and/or retrieval.

SUMMARY OF THE INVENTION

Thus, this invention includes novel occlusive compositions as well asmethods of using and making these compositions.

In certain aspects, the invention includes a vaso-occlusive devicecomprising an inner member having an axial length; a substantiallytubular expandable member disposed around the inner member, wherein theexpandable member slides along at least a portion of the axial length ofthe inner member; and a stop element attached to the inner member. Theexpandable member may comprise a braid configuration and the innermember may comprise a coil configuration. Furthermore, the expandablemember and/or the inner member may comprise one or more metals (e.g.,nickel, titanium, platinum, pallidum, rhodium, gold, tungsten, iridiumand alloys or combinations thereof) or metal alloys (e.g., a stainlesssteel or super-elastic metal alloy such as nitinol). In certainembodiments, the stop element comprises a polymer.

Any of the devices described herein may further comprise a severablejunction detachably which may be connected to a pusher element. Thedetachment junction can be positioned anywhere on the device, forexample at one or both ends of the device. In certain embodiments, theseverable junction(s) are, an electrolytically detachable assemblyadapted to detach by imposition of a current; a mechanically detachableassembly adapted to detach by movement or pressure; a thermallydetachable assembly adapted to detach by localized delivery of heat tothe junction; a radiation detachable assembly adapted to detach bydelivery of electromagnetic radiation to the junction or combinationsthereof. The detachment junction(s) may be attached to inner member,expandable member and/or stop element.

Any of the devices described herein may further comprise one or moresliding elements disposed around the inner member. The expandable memberis typically attached to the sliding element(s). In certain embodiments,the sliding element comprises polymer.

In any of the devices described herein, the expandable member may beattached to the inner member in at least one location.

Any of the devices (or individual components of the devices) describedherein may further comprise one or more additional components, forexample bioactive and/or biodegradable agents.

In another aspect, the invention includes a method of occluding a bodycavity comprising introducing any of the vaso-occlusive devicesdescribed herein into a body cavity (e.g., an aneurysm).

These and other embodiments of the subject invention will readily occurto those of skill in the art in light of the disclosure herein.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 depicts a side-view cross-section of an exemplary assembly asdescribed herein having a coil-shaped inner member and a braidedexpandable member. The proximal end of the expandable member isslideably attached to the inner member. An internal stop element isshown attached to the inner member near the sliding portion of theexpandable member.

FIG. 2 depicts a side-view cross-section of an exemplary assembly asdescribed herein having a coil-shaped inner member, a braided expandablemember and an internal stop element. In this embodiment, the expandablemember is attached at its proximal end to a distinct sliding element andis slideably attached at its distal end directly to the inner member.The distinct sliding element is positioned proximal to stop element.

FIG. 3 depicts a side view cross-section of another exemplary assemblyas described herein having a coil-shaped inner member and a braidedexpandable member attached at its proximal end to a sliding element. Inthis embodiment, the external stop element comprises a cuff-likestructure surrounding the inner member and positioned proximal to thesliding element.

FIG. 4 depicts a side-view cross-section of another exemplary assemblyas described herein having a coil-shaped inner member and a braidedexpandable member attached at both ends to sliding elements distinctfrom the expandable member. Two internal stop elements are depictedsurrounding the inner member and positioned between the optionallydistinct sliding members. Each stop element is depicted as a flaredcuff-like structure.

FIG. 5 depicts a side-view cross-section of another exemplary assemblyas described herein having a coil-shaped inner member and a plurality ofbraided expandable members. Each expandable member is attached at itsproximal end to a distinct sliding element and at its distal end toanother distinct sliding element. The distinct sliding elements surroundthe inner member. This variation comprises a plurality of internal stopelements, each comprising a flared cuff-like structure surrounding theinner member and positioned between the sliding elements of eachexpandable member.

FIG. 6 depicts a side-view cross-section of another exemplary assemblyas described herein having a coil-shaped inner member and a braidedexpandable member. In this embodiment, the expandable member is attachedto two sliding elements, one at the proximal end of the braid and one atthe distal end of the braid. The proximal sliding element is alsoattached to the inner member by external string-like stop elements.Additional internal stop element(s) are positioned between the slidingelements.

FIG. 7 depicts a side-view, cross section of an exemplary device similarthat depicted in FIG. 6. In the variation shown in FIG. 7, external stopelements in the form of strings (e.g., sutures) extend from the distinctdistal sliding element to the distal end of the inner member.

FIG. 8 depicts a side-view, cross-section of another exemplary deviceincluding multiple expandable segments and multiple external stopelements.

FIG. 9 depicts a side-view, cross-section of another variation in whichthe external stop elements are detachable from the inner member suchthat upon deployment, the inner member can be removed and the expandablemember left in the target site.

FIG. 10 depicts a side-view, cross-section of the embodiment shown inFIG. 9 within a delivery catheter. The dark arrow shows the direction ofmovement. When the device is pulled back through the catheter as shown,the external proximal stop elements are taut and the distal stopelements are slack.

FIG. 11 depicts a side-view, cross-section of the embodiment shown inFIG. 9 within a delivery catheter. The dark arrow shows the direction ofmovement. When the device is pushed through the catheter as shown, theexternal distal stop elements are taut and the proximal stop elementsare slack.

FIG. 12 depicts an exemplary device (10) as described herein as deployedwithin an aneurysm (80).

DESCRIPTION OF THE INVENTION

Occlusive (e.g., embolic) compositions are described. The compositionsdescribed herein find use in vascular and neurovascular indications andare particularly useful in treating aneurysms, for examplesmall-diameter, curved or otherwise difficult to access vasculature, forexample aneurysms, such as cerebral aneurysms. Methods of making andusing these vaso-occlusive elements also form aspects of this invention.

All publications, patents and patent applications cited herein, whetherabove or below, are hereby incorporated by reference in their entirety.

It must be noted that, as used in this specification and the appendedclaims, the singular forms “a”, “an”, and “the” include plural referentsunless the content clearly dictates otherwise. Thus, for example,reference to a device comprising “a stop element” includes devicescomprising of two or more elements.

The device is a surgical implement and can be readily deployed, removedand/or repositioned in human vasculature. It is also suitably flexibleto be placed in the distal tortuous vasculature of the brain.

Typically, the devices include an inner member (which may beremoveable), one or more expandable members and one or more stopelements. The expandable member is capable of sliding along at least aportion of the length of the inner member. The sliding element may bedistinct from the expandable member or may be integral to the expandablemember, for example, by ensuring that selected portions of theexpandable member slide in relation to the inner member.

Depicted in the Figures are exemplary embodiments of the presentinvention in which the inner member is depicted as a coil and theexpandable member is depicted as a braided element. It will beappreciated that this is for purposes of illustration only and that theexpandable member and/or inner member can be of other materials orshapes, for example as described in U.S. patent application Ser. No.10/745,911, incorporated by reference in its entirety herein.

FIG. 1 depicts an exemplary embodiment of the inventive vaso-occlusivedevices described herein. The device as a whole is generally designated(10). Also shown are detachment junction (15), pusher wire (25),deployment device (e.g., catheter) (35), inner member (20), expandablemember (30) and stop element (40). Stop element (40) is internal to theexpandable member (30), is bonded to inner member (20) and does notmove. The diameter of stop element (40) is such that it engages theexpandable member (30) as the device (10) is moved through deploymentcatheter (35) and thereby limits bunching and overexpansion of theexpandable element in the catheter (35). As discussed below, stopelement(s) may be positioned at any suitable location, so long as theyserve this function. In the embodiment shown in FIG. 1, the stop element(40) is positioned near the proximal sliding portion (50) of theexpandable member (30).

As shown in FIG. 1, sliding element (50) is integral to (e.g., formedfrom) the expandable member (30). Integral sliding element (50) slidesin an axial direction along the inner member (20) near the distal andproximal ends of the inner member (20). The distal end of the expandablemember is also attached (51), either fixedly or slideable, to the coil.It will be readily apparent that the expandable member can be madeslideable in relation to the inner member by a variety of ways,including, for example, cinching of the expandable members to formslideable portions. Further, the expandable member (30) can bepermanently or temporarily attached to the inner member by any suitableattachment mechanism.

FIG. 2 shows an exemplary embodiment that includes an expandable member(30) having a distinct sliding element (55) at is proximal end. Distinctsliding element (55) is disposed around the inner member (20) andattached to the expandable member (30). At its distal end, theexpandable member may be fixedly or slideably attached (50) to the coil.Distinct sliding element (55) can only slide distally until it reachesthe internal stop element (40). Thus, stop element (40) serves toprevent the expandable member (30) from over-expanding during deliveryand/or retrieval.

FIG. 3 shows another variation including a cuff-shaped external stopelement (40) attached to the proximal end of the inner member (20) andproximal to distinct sliding element (55). Expandable member (30) isalso attached to the distal end of the inner member (20), either viadirect attachment to the inner member or via an intermediate element.When present, the intermediary element may be fixedly attached to theinner member (20) or may be removable from the inner member (20), forexample an additional sliding element.

FIG. 4 shows another embodiment having two internal stop elements (40)positioned between two sliding elements (50). In this embodiment, stopelements (40) have a flared cuff-like configuration, with the flaredside facing the sliding element (50). In this variation, expandablemember (30) is attached to distinct sliding elements (55) disposedaround inner member.

FIG. 5 shows another embodiment including multiple expandable members(30), multiple stop elements (40), multiple integral sliding elements(50) and multiple distinct sliding elements (55). Each expandable member(30) is attached at its proximal end to a sliding element (50, 55) andat its distal end to another sliding element (50, 55). Two flaredcuff-like stop elements (40) are fixed to the inner member (20) and arepositioned between the proximal and distal ends of each pair of slidingelements (50, 55). Inner member (20) can slide with respect to bothexpandable members (30).

FIG. 6 shows another variation including internal (40) and external (70)stop elements. Expandable member (30) is attached to distinct slidingelements (55). Internal stop element (40) is fixed to the inner member(20) and is positioned proximal and near to the distal sliding member(55) when the expandable member (30). External stop elements (70) areattached to the proximal sliding element (55) and to proximal end ofinner member (20). External stop elements (70) can be any material, forexample a suture that is slack when the assembly is moved in one axialdirection and engages the expandable member with the inner member whenthe assembly is moved in the other axial direction.

FIG. 7 shows another variation in which multiple external stop elements(70) are used in conjunction with multiple distinct sliding elements(55).

FIG. 8 shows another variation including multiple segments of expandablemembers (30), integral sliding elements (50) and external stop elements(70).

FIG. 9 shows yet another embodiment in which detachment junctions (15)are included on external stop elements (70). In this variation, theinner member can be removed after the expandable member (30) has beendeployed. Removing the inner member creates a lumen into which it may bepossible to add larger volumes of additional (e.g., bioactivecomponents), for example to the inside of the expandable member (30). Inaddition, expansion of the expandable member (30) may be more completein the absence of an inner member (20).

Thus, a variety of embodiments can be used to the devices describedherein allow for the efficient deployment of expandable devices into anytarget vessel.

The expandable member may assume a variety of structures including, butnot limited to, braids, coil, stents (e.g., self-expanding stents) andcombinations of these. By “expandable,” is meant that the elementincreases in diameter along its primary axis. See, also, U.S. patentapplication Ser. No. 10/745,911. The overall structure of the expandablemember is preferably tubular, although as shown in the drawings, thediameter of this element is not necessarily constant along its length.Furthermore, in addition to expanding along its primary axis upondeployment, the overall three-dimensional configuration of theexpandable member typically changes change upon deployment from thepre-deployment linear, tubular configuration. For example, theexpandable member may form a coil configuration or may have asubstantially random space-filling relaxed configuration (FIG. 12) upondeployment.

With regard to materials, it is to be understood that the expandablemember may be made of a variety of materials, including but not limitedto metals, polymers and combinations thereof. See, e.g., U.S. Pat. Nos.6,585,754 and 6,280,457 for a description of various polymers. Incertain embodiments, the expandable member is a braided structurecomprising one or more metals or metal alloys, for example, PlatinumGroup metals, especially platinum, rhodium, palladium, rhenium, as wellas tungsten, gold, silver, tantalum, stainless steel and alloys of thesemetals. Preferably, the expandable member comprises a material thatmaintains its shape despite being subjected to high stress, for example,“super-elastic alloys” such as nickel/titanium alloys (48-58 atomic %nickel and optionally containing modest amounts of iron); copper/zincalloys (38-42 weight % zinc); copper/zinc alloys containing 1-10 weight% of beryllium, silicon, tin, aluminum, or gallium; or nickel/aluminumalloys (36-38 atomic % aluminum). Particularly preferred are the alloysdescribed in U.S. Pat. Nos. 3,174,851; 3,351,463; and 3,753,700.Especially preferred is the titanium/nickel alloy known as “nitinol.”The expandable member may also comprise a shape memory polymer such asthose described in International Publication WO 03/51444. Preferably,the expandable member is free of any hydrogels (substances that are gelsin an aqueous environment and expand to at least 10 times their originalsize upon contact with water), but may include one or more non-hydrogelpolymers that do expand.

Like the expandable member, the inner member may assume a variety ofstructure and be comprised of a variety of materials. Thus, althoughdepicted in the Figures as a coil (e.g., platinum coil), the innermember may be of a variety of shapes or configuration including, but notlimited to, braids, wires, knits, woven structures, tubes (e.g.,perforated or slotted tubes), injection-molded devices and the like.See, e.g., U.S. Pat. No. 6,533,801 and International Patent PublicationWO 02/096273. The inner member may be made of any of the materialsdescribed above, for example, metals (e.g., platinum group metalsdescribed above), metal alloys, polymers or combinations of thesematerials. In addition, the inner member may be coated with one or morebiodegradable and/or bioactive coatings, for example as described inU.S. Pat. No. 6,280,457. In certain embodiments, the inner member is aplatinum coil. The inner member may also change shape upon release fromthe restraining member, for example change from a constrained linearform to a relaxed, three-dimensional configuration upon deployment.However, the inner member does not expand along its primary axis in thesense of the expandable member.

As noted above and shown in the Figures, the expandable member slidesalong a portion of the inner member. The sliding elements may beintegral to the expandable member (e.g., portions of the expandablemember can be made to slide in relation to the inner member) and/or maybe distinct from the expandable member. Integral sliding elements can bemade in a variety of ways including, for example, by cinching theexpandable member to a diameter slightly larger than the inner and/or bybonding/attaching the expandable member to a piece of polymeric tubingsuch as Teflon™ that is typically of a diameter slightly larger than theinner member. Distinct sliding element(s) are typically disposed aroundthe inner member (20). Combinations of integral and distinct slidingelements can be used in one device.

Integral and/or distinct sliding element(s) can be made of any number ofmaterials, for example metals and polymers described above including butnot limited to, stainless steel, platinum, kevlar, PET, carbothane,cyanoacrylate, epoxy, poly(ethyleneterephthalate) (PET),polytetrafluoroethylene (Teflon™), polypropylene, polyethylene,polyglycolic acid, polylactic acid, nylon, polyester, fluoropolymer, andcopolymers or combinations thereof.

An important feature of the devices described herein is the inclusion ofone or more stop elements that limit the expansion of the expandablemember in the delivery mechanism (e.g., delivery catheter). Generally,the stop elements function to engage the expandable member with theinner member (e.g., at the proximal and/or distal ends), thereby keepingthe diameter of the expandable member constrained within the deploymentdevice. Thus, stop element(s) are positioned anywhere on the device thatserves limit the expansion of the expandable member during deployment,re-positioning and/or retrieval.

Stop elements can be external and/or internal to the expandable member.Both external and internal stop elements are generally fixedly attachedto the inner member in at least one location, although in certainembodiments, they may be detachable.

Exemplary internal stop elements include bumper-like shape (FIG. 2),flared cuff-like shapes (e.g., FIGS. 4, 5) and the like. It will beapparent that the internal stop elements can take other shapes, forexample, rounded structures, bumps, etc. Whatever shape of the stopelement, it may be fixed or may be capable of assuming an open, flaredconfiguration, for example when engaged by sliding of the expandablemember along the inner member. Other configurations such as prongs,hooks (both fixed or expandable when engaged) and the like can alsoemployed for internal stop elements.

Exemplary external stop elements include cuff-like structures (FIG. 3)and string like structures (FIGS. 6 to 8) such as wires, strings,sutures and/or other suitable string-like materials. External stopelements may also take the form of prongs, hooks and the like. Externalstop element(s) are preferably bonded to the inner member (20) or may bedetachable from the inner member (20) and/or pusher wire (25) (FIGS. 9,10).

Stop elements of similar or different configurations (e.g., externaland/or internal) can be used in the same device. For instance, FIG. 6shows a device including a bumper type stop element as well as a stringtype stop element. Stop elements (internal and/or external) can be madeany material, for example, metals and polymers described above includingbut not limited to, stainless steel, platinum, kevlar, PET, carbothane,cyanoacrylate, epoxy, poly(ethyleneterephthalate) (PET), polypropylene,polyethylene, polyglycolic acid, polylactic acid, nylon, polyester,fluoropolymer, and copolymers or combinations thereof.

Pusher wire (25) or other elements may be made of, or coated with, amaterial such as polytetrafluoroethylene (e.g., Teflon™) and desirablyextends all the way to the proximal end of the catheter. The pusher wire(25) may be rotatable and axially moveable with respect to the device.Pusher wire (25) can also act as a guidewire and may be used to providea pathway through tortuous vasculature for the device to follow.

Any of the devices described herein may further comprise a detachmentjunction (15), which is severable. The detachment junction (15) may beconnected to a pusher element, such as a pusher wire. The detachmentjunction can be positioned anywhere on the device, for example at one orboth ends of the device.

In certain embodiments, the inner member may be removed afterdeployment. As shown in FIG. 9, the detachment junctions (15) arepositioned so that only the expandable member is detached from theassembly and the inner member can be withdrawn. The detachment junction(15) may be the pusher wire (25) itself. Alternatively, as depicted inFIG. 9, detachment may be from a separate element (45), for example aconductive wire element suitable for electrolytic detachment. The wireis typically insulated until the detachment junction (15). In thisembodiment, pusher wire (25) is typically a metal and polymer composite.

The severable junction(s) may be detached in a variety of ways, forexample using an electrolytically detachable assembly adapted to detachby imposition of a current; a mechanically detachable assembly adaptedto detach by movement or pressure; a thermally detachable assemblyadapted to detach by localized delivery of heat to the junction; aradiation detachable assembly adapted to detach by delivery ofelectromagnetic radiation to the junction or combinations thereof.Furthermore, the detachment mechanism may be hydraulic, for example thepusher wire may be cannulated, for example to allow for saline injectionthrough the pusher wire to push off the coil.

The devices described herein may also comprise additional components,such as co-solvents, plasticizers, coalescing solvents, bioactiveagents, antimicrobial agents, antithrombogenic agents (e.g., heparin),antibiotics, pigments, radiopacifiers and/or ion conductors which may becoated using any suitable method or may be incorporated into theelement(s) during production. See, e.g., co-owned U.S. patentapplication Ser. No. 10/745,911, U.S. Pat. No. 6,585,754 and WO02/051460, incorporated by reference in their entireties herein. Thebioactive materials can be coated onto the device (e.g., heparin) and/orcan be placed in the vessel prior to, concurrently or after placement ofone or more devices as described herein. For example, in embodiments inwhich the inner member is removed after deployment of the expandablemember, one or more bioactive materials can be delivered to the lumen ofthe expandable member.

As noted elsewhere, the location of the device is preferably visibleusing fluoroscopy. A highly preferred method is to ensure that at leastsome of the elements (e.g., expandable member and/or inner member)making up the device are provided with significant radio-visibility viathe placement of a radio-opaque covering on these elements. A metalliccoating of a metal having comparatively more visibility, duringfluoroscopic use, than stainless steel is preferred. Such metals arewell known but include gold and members of the Platinum Group describedabove.

One of more of the elements may also be secured to each other at one ormore locations. For example, to the extent that various elements arethermoplastic, they may be melted or fused to other elements of thedevices. Alternatively, they may be glued or otherwise fastened.Furthermore, the various elements may be secured to each other in one ormore locations.

Methods of Use

The embolic compositions described herein are often introduced into aselected site using the procedure outlined below. This procedure may beused in treating a variety of maladies. For instance in the treatment ofan aneurysm, the aneurysm itself will be filled (partially or fully)with the compositions described herein.

Conventional catheter insertion and navigational techniques involvingguidewires or flow-directed devices may be used to access the site witha catheter. The mechanism will be such as to be capable of beingadvanced entirely through the catheter to place vaso-occlusive device atthe target site but yet with a sufficient portion of the distal end ofthe delivery mechanism protruding from the distal end of the catheter toenable detachment of the implantable vaso-occlusive device. For use inperipheral or neural surgeries, the delivery mechanism will normally beabout 100-200 cm in length, more normally 130-180 cm in length. Thediameter of the delivery mechanism is usually in the range of 0.25 toabout 0.90 mm. Briefly, occlusive devices (and/or additional components)described herein are typically loaded into a carrier for introductioninto the delivery catheter and introduced to the chosen site using theprocedure outlined below. This procedure may be used in treating avariety of maladies. For instance, in treatment of an aneurysm, theaneurysm itself may be filled with the embolics (e.g. vaso-occlusivemembers and/or liquid embolics and bioactive materials) which causeformation of an emboli and, at some later time, is at least partiallyreplaced by neovascularized collagenous material formed around theimplanted vaso-occlusive devices.

A selected site is reached through the vascular system using acollection of specifically chosen catheters and/or guide wires. It isclear that should the site be in a remote site, e.g., in the brain,methods of reaching this site are somewhat limited. One widely acceptedprocedure is found in U.S. Pat. No. 4,994,069 to Ritchart, et al. Itutilizes a fine endovascular catheter such as is found in U.S. Pat. No.4,739,768, to Engelson. First of all, a large catheter is introducedthrough an entry site in the vasculature. Typically, this would bethrough a femoral artery in the groin. Other entry sites sometimeschosen are found in the neck and are in general well known by physicianswho practice this type of medicine. Once the introducer is in place, aguiding catheter is then used to provide a safe passageway from theentry site to a region near the site to be treated. For instance, intreating a site in the human brain, a guiding catheter would be chosenwhich would extend from the entry site at the femoral artery, up throughthe large arteries extending to the heart, around the heart through theaortic arch, and downstream through one of the arteries extending fromthe upper side of the aorta. A guidewire and neurovascular catheter suchas that described in the Engelson patent are then placed through theguiding catheter. Once the distal end of the catheter is positioned atthe site, often by locating its distal end through the use of radiopaquemarker material and fluoroscopy, the catheter is cleared. For instance,if a guidewire has been used to position the catheter, it is withdrawnfrom the catheter and then the assembly, for example including thevaso-occlusive device at the distal end, is advanced through thecatheter.

Once the selected site has been reached, the vaso-occlusive device isextruded, for example by loading onto a pusher wire. Preferably, thevaso-occlusive device is loaded onto the pusher wire via a mechanicallyor electrolytically cleavable junction (e.g., a GDC-type junction thatcan be severed by application of heat, electrolysis, electrodynamicactivation or other means). Additionally, the vaso-occlusive device canbe designed to include multiple detachment points, as described inco-owned U.S. Pat. Nos. 6,623,493 and 6,533,801 and International Patentpublication WO 02/45596. They are held in place by gravity, shape, size,volume, magnetic field or combinations thereof.

During deployment, it is possible that friction may be created when thedevice is moved through the deployment mechanism (e.g., catheter), forexample by the force exerted by the linearly constrained expandablemember on the walls of the catheter. As noted above, the devicesdescribed herein include one or more stop elements that may limitbunching and expansion of the expandable member during deployment. Asdepicted in FIGS. 10 and 11, the stop elements (70, 75) keep theexpandable member (30) taut as it is pushed through the deliverycatheter (35). This reduced friction against the walls of the deliverycatheter and eases delivery. FIG. 10 shows a device as described hereinas it is pulled back through a deliver catheter (35). The dark arrowshows the direction of motion. As the device is pulled back, theproximal stop elements (70) are taut while the distal stop elements (75)are slack. FIG. 11 shows a device as described herein as it is pushedout of a delivery catheter. As the device is pushed, distal stopelements (75) are taut while proximal stop elements (70) are slack.Thus, in either axial direction, the stop elements cause the expandablemember (30) to engage the inner member (20) and assume a lower profile(smaller diameter) that makes movement through the catheter (35) easier.

As noted above with regard to FIG. 9, it will also be apparent that incertain embodiments, the inner member (20) is removeable afterdeployment into the vessel. For example, the device can be deployed intoa vessel (aneurysm) as described herein. Once deployed, the expandablemember (30) is detached from the inner member (20) while the innermember (20) remains attached to the pusher wire (25) and can be removedfrom the vessel.

It will also be apparent that the operator can remove or reposition(distally or proximally) the expandable member. For instance, theoperator may choose to insert a device as described herein, beforedetachment, move the pusher wire to place the device in the desiredlocation.

Modifications of the procedure and vaso-occlusive devices describedabove, and the methods of using them in keeping with this invention willbe apparent to those having skill in this mechanical and surgical art.These variations are intended to be within the scope of the claims thatfollow.

1. A method of occluding an aneurysm comprising introducing avaso-occlusive device into the aneurysm such that the vaso-occlusivedevice assumes its relaxed, three-dimensional configuration within theaneurysm, thereby occluding the aneurysm, the vaso-occlusive devicecomprising: an implantable vaso-occlusive device having a linearconfiguration within a restraining member and a relaxed,three-dimensional configuration upon release from the restrainingmember, the linear configuration of the device comprising an innermember having an axial length: a substantially tubular expandable memberdisposed around the inner member, wherein the expandable member slidesalong at least a portion of the axial length of the inner member; a stopelement attached to the inner member; and a detachment junction; andwherein the relaxed, three-dimensional configuration of the implantedvaso-occlusive device is adapted to be placed within an aneurysm suchthat the device occludes the aneurysm.
 2. The method of claim 1, whereinthe stop element comprises a polymer.
 3. The method of claim 1, whereinthe expandable member comprises a braid configuration.
 4. The method ofclaim 1, wherein the inner member comprises a coil.
 5. The method ofclaim 1, wherein the expandable member comprises a metal.
 6. The methodof claim 5, wherein the metal is selected from the group consisting ofnickel, titanium, platinum, gold, tungsten, iridium and alloys orcombinations thereof.
 7. The method of claim 6, wherein the metal isnitinol or platinum.
 8. The method of claim 1, wherein the inner membercomprises a coil comprising a metal selected from the group consistingof platinum, palladium, rhodium, gold, tungsten and alloys thereof. 9.The method of claim 1, wherein the inner member comprises a coilcomprising a stainless steel or super-elastic metal alloy.
 10. Themethod of claim 4, wherein the coil member comprises nitinol.
 11. Themethod of claim 1, wherein the detachment junction comprises anelectrolytically detachable end adapted to detach from a pusher byimposition of a current on the pusher.
 12. The method of claim 1,wherein the detachment junction is attached to the inner member.
 13. Themethod of claim 1, wherein the detachment junction is attached to thestop element.
 14. The method according to claim 1, further comprising asliding element disposed around the inner member, wherein the expandablemember is attached to the sliding element.
 15. The method of claim 14,wherein the sliding element comprises a polymer.
 16. The method of claim1, wherein the expandable member is attached to the inner member in atleast one location.
 17. The method of claim 1, further comprising anadditional component.
 18. The method of claim 17, wherein the additionalcomponent is bioactive.